Interchangeable sprocket



E. B. GRACE.

INTERCHANGEABLE SPROCKET. APPLcATmN FILED APn.24, 191s.

1,360,930. Patented Nov. 30, 1920.

Edwin B Grace. @5% W 4 1H-MQ UNITED STATES i PATENT OFFICE.

EDWIN E. GRACE, or MEMPHIS, TENNESSEE.

INTERCHANGEABLE SPROCKET.

Application filed April 24, 1918. Serial'No.

To @ZZ whom t may concern.'

Be it known that I, EDWIN B. GRACE, a citizen ofthe United States,residing at Memphis, Shelby c0unty,'and State of Tennessee, haveinvented and discovered certainnew and useful Improvements inInterchangeable Sprockets, of which the follow- 1n is a specification. I

y said invention relates. to sprocket wheels and means for mounting the`same,

particularly sprockets of thev type used in film machines and consistsin the combinations and arrangements of elements hereinafter describedand particularly set forth in the accompanying claims.

The invention has for its purpose to provide a'sprocket wheel,preferably of the dupleX type, with a removable tooth carrylng portionto the end that the same may be readily replaced when wornand therebynotrequire the discarding of the sprocket as a whole when only the teethare defective.

The invention as disclosed herein is particularly applicableto movingpicture machines, both projectors and cameras, and is shown by way ofillustration in the accompanying drawings wherein:

igure 1 is a part elevation and part sectional view of the duplexsprocket wheel, Fig. 2, a transverse sectional-and partly.

elevational view thereof,

Flg. 3, a view similar to Fig. 1, showing a modified forInXof the devicefor use on the portions 6 and hub feed or take-up shaft of a motionpi/cture machine, and

, Fig. 4, a detail section showing a modified form of key. V-

Referring to the construction in further detail and .wherein likereference characters designate corresponding parts in the differentviews shown, the sprocket consists of'a sleeve portion 5 having integralend disk (5, 6 and 7 forming what is usually termed the spool. The hubportions are rabbeted as at 8, and the rabbeted portions -are ofpolygonal design (see Fig. `2) to receive the toothed disk portions 9that have central openings to readily fit thereon as shown. The extremehub portions 10 areeXternally threaded as at 11 to receive the outer andclamping disks 12'that screw-thread thereon closely against `the outersurfaces of said toothed disks as will be understood.

Each of the locking disks 12 is provided with aplurality of apertures 13to receive Specification of Letters Patent.

portions 7, said parts Patented Nov. 30, 1920.

w the engaging elements of a Spanner for apreduce the weight o'f theclamping members 12 and for a like reason the inner and integral diskportions 6 have openings 14.

The peripheries of the two disk members for each set of sprocket teeth15 afford the necessary'bearingsurface for the 61m after the manner ofthe sprockets now used. And the construction of the sprocket teeth perse readily allows said teeth to engage with and dlsengage from the rowsof apertures in the moving film Without liabilityof tearing, or causingexcessive wearing to any particular parts of the'teeth.

To hold the sprocket in position on the shaft, tapered locking pins, orthreaded keys, 16, are provided to lit within tapering apertures 17which pass transversely through the shaft 18 .as shown.

said keys has its larger end 19 provided portion 5, and a 'notch 22serves to receive Each of a screw driver for fastening or releasing lsaid key. On some motion picture projectors but one pin is required toanchor the intermittent procket, and in such cases the combination pinand set screw may be applied to the Acenter opening 23.

Referring to Fig. 3 a sleeve 24 is provided to take up the space betweenthe spool or duplex sprocket and the shaft 25 in instances where saidshaft is smaller than the bore of the -sprocket as in the cases of thefeed or take-up shaft ofthe machine. In brief the provision of thereducer sleeve 24 renders the device applicable to be fitted on n any ofthe three shafts of the ordinary projecting or camerafmotion z'. e. thesprocket may a ply to either the intermittent movement, t e top feed, orthe take-up feed 0f the ma'ch-ine. A screw bolt or stud 26 engages withthe hub sleeveA 5 and reducer sleeve 24 and secures these elementstogether and to the shaft 25 as shown. It is proposedy to construct thespoolv (5 and 6) and the retainer disks '(12) of aluminum', and theinterchangeable sprocket disks (9) together with the combination pinsand set screws (16) of steel, but other materials may of course be used.

The provision of the combination pins and set screws for securing thesprocket permits the entire intermittent movement of a picture machinelll of a hub having integral end disk portions,

machinevto be removed Without disturbing the original position of theeccentric bushings and avoids the likelihood of springing theintermittent shaft. Thus by accomplishing such a result considerabletime `and money are saved which amply demonstrates the simplicity andutility of this type of fastening means. In brief, its provision enablesthe accomplishing of Work by unskilled hands Which heretofore could bedoney only by highly skilled labor.

Having thus fully described my said irivention, What' I claim asnevv anddesire to secure by Letters Patent, is:

l. In a sprocket Wheel, the combination and polygonal hub portionsformed on said disk portions, toothed disks having corre@ `spondingapertures fitted on said hub portions, said hub portions having threadedshoulders, and disks mounted on said shoultions, toothed disks removablyfitted on such rabbeted hub portions, and disks screwthreaded on the huband locking the toothed disks to the hub.

In Witness whereof, I have hereunto set my hand and seal at Memphis,Tennessee, this 18th day of April, A. D. nineteen hundred and eighteen.

EDWIN B.v GRACE. [Ls] Witnesses:

C. L. ROMAN, J oHN W. FARLEY.

